Memory subsystems with several mass memories are known, such as, so-called RAID systems (redundant array of independent disks). They are used especially in server systems in which the data processing unit and the memory subsystem are often separated from each other. Especially for very powerful server systems, for example, so-called server farms, the memory subsystems often limit the performance of the overall system. For example, so-called streaming applications in which a server processes large amounts of data sequentially require especially short access times and high data transfer rates and storage capacities.
From the state of the art, different mass memories are known. Mass memory systems with at least one moving read/write head or moving storage medium, for example, magnetic, magneto-optical, or optical hard drives, are relatively widespread. Such hard drives are characterized by very high data capacities and densities and are relatively economical in production. Especially through a logical connection of several such drives, relatively simple mass memories with a few terabytes of storage capacity can be constructed. Mass memories with moving read/write heads or memory media, however, feature the disadvantage that the moving part must first be positioned before the data access, which currently causes an access delay of several milliseconds. Thus, such mass memories are not suitable for use with applications that place very high demands on access times, especially so-called real-time applications.
In addition, solid-state memory media are known from the prior art. For example, so-called solid-state disks (SSD) use a plurality of semiconductor memory components to store data. Here, in particular, non-volatile EPROM components or battery-buffered RAM components are used. Such solid-state memory media are characterized by very high access speeds, since each of the included memory cells can be directly accessed. Currently, access times in the range of a few nanoseconds are possible. Such solid-state memory media, however, feature the disadvantage that they are relatively expensive and feature a comparatively low memory density and capacity. Therefore, they are not suitable for storing very voluminous data, for example, in the range of several hundred gigabytes.